POTSDAM, N.Y. — Nearly three years after a 12-year-old boy’s slaying shocked this small northern New York village, a college soccer coach was charged with suffocating and strangling the child, who was his ex-girlfriend’s son, authorities said Friday.

Oral “Nick” Hillary, the men’s soccer coach at Clarkson University, was arrested Thursday at his home in Potsdam and charged with second-degree murder in Garrett Phillips’ killing, police said.

The boy was found unconscious inside his home after neighbors heard screams and cries for help on Oct. 24, 2011. He had been strangled and suffocated with a pillow, authorities said.

Hillary was being held without bail Friday in the St. Lawrence County Jail. A message left with his lawyer, Christopher Renfroe of Queens, wasn’t returned.

District Attorney Mary Rain said details of the case weren’t being disclosed, including the evidence presented to a grand jury. She said Hillary and his teenage daughter had lived with Tandy Collins, Garrett’s mother, and her two sons, but she broke off the relationship in August 2011. By the time Garrett was killed, Hillary was living elsewhere in Potsdam, Rain said.

Officials at Clarkson University, a Division III school, said Hillary is on administrative leave.

The killing shocked Potsdam, a college town of about 9,400 residents 20 miles from the Canadian border. Rain said she made the case a priority when she took office Jan. 1.

“Garrett was such an outgoing young man and he had so many friends,” Rain said. “He was just one of those kids that everybody loved.”

Hillary was a soccer star at rival St. Lawrence University in nearby Canton. According to the Clarkson athletic department’s website, Hillary was four-year starter and two-year captain at St. Lawrence, leading the Saints to a 22-0-0 record and the Division III national championship in 1999. A 2000 St. Lawrence graduate, he was an assistant coach at his alma mater before being named Clarkson’s head coach six years ago.

A native of Jamaica, Hillary coached high school and club soccer teams in the Tampa-St. Petersburg, Florida, area before moving back north. He’s is a 1993 graduate of Samuel J. Tilden High School in Brooklyn, New York.

He has four other children, including 1-year-old twins, with another woman, Rain said.